1. Field
This application generally relates to laparoscopic scissors and, more particularly, to laparoscopic scissors with blades having a parabolic cutting profile and to a mechanism for actuating the blades of the scissors.
2. Discussion of the Relevant Art
Laparoscopic surgical instruments or devices that use actuatable blades, such as laparoscopic scissors are typically activated by some mechanical means. In some cases, the surgical instruments or devices use an actuation rod to translate motion from a handle at one end to a blade at the opposite end of the device. Common to laparoscopic scissors is an actuation rod that includes a pin that works in conjunction with a slot in the blades. Moving the actuation rod cams the pin in the slot, which opens and closes the scissor blades.
In previous arrangements, the blades typically have slots proximal to a pivot location and, because of this configuration, the proximal portions, or back ends, of the blades are typically relatively large. Thus, with prior laparoscopic scissors, when the blades are in their open position, the proximal portions of the blades extend out beyond the outside diameter of the scissors shaft and look like “wings.” This high-profile extension may be a problem for the user and, in particular, the patient as the extended “wings” can catch on or interfere with tissue or other devices during use.
When used on scissors, these wings can be covered by a plastic shrink tubing to insulate all the metal components during electro-surgical cautery. However, when the blades are open, the wings can stretch and deform the shrink tubing. This deformation can be problematic in that when the scissors are withdrawn from a trocar, the deformed tubing may not relax and it may catch on the end of the cannula, thereby pulling the trocar out of the patient.